[unreadable] Rats are very important laboratory animals for studying mammalian biology. These rodents are especially useful for physiological, neurobehavioral, organ transplantation, and toxicological studies. In addition, exceptional genetic and genomic resources are now available for the rat, including a genome that has been sequenced with a current assembly and annotation predicting 23,400 genes (www.ensembl.org/Rattus_norvegjcus) and more than 50,000 expressed sequence tags (ESTs). The rat model system is now primed for functional genomic studies. However, one particularly valuable resource to facilitate studies of gene function that is sorely lacking in the rat system is a large collection of mutants and a continuous source of new mutations. Although it is possible to routinely generate transgenic rats to express exogenous genes, there are no embryonic stem (ES) cells for this species that could be used to generate targeted mutations that is routine in the mouse. The ability to easily generate new mutant rat strains would significantly advance the use of this central laboratory animal for biomedical research. The primary objective of this proposal is to generate a Sleeping Beauty transposon mutagenesis system through transgenic rats to serve as a freely available resource to the research community to easily generate and molecularly identify new mutations in rats. [unreadable] [unreadable] [unreadable]